Thursday. I think I'm fully 2 weeks behind on astro-ph reading. I plan to catch up on Christmas (haha). Cris didn't write back. I'm starting to worry about his family.
1203.6062
Radiative transfer and radiative driving of outflows in AGN and starbursts
Novak, Ostriker, Ciotti
Outline a method for treating the radial forces on interstellar gas due to absorption of photons by dust grains (for BH fueling, SF, and galactic feedback studies). Gives correct behavior in the limits of: dominated by central point source, isotropic source, optically thin; thick to UV/optical; thick to IR. Can interpolate between limits reasonably. Explicitly energy conserving (photons absorbed and redistributed to the IR). Implement in 2d hydro code on early-type galaxies. Find: dynamics and final state of simulations affected by radiative forces on dust; even when dust-to-gas ratio varied from zero to MW value. In ULIRGS with high gas densities and SFR~100 Msun/yr, dust makes a more substantial contribution to the dynamics and outcome of the simulation. Find: despite the large opacity of dust to UV radiation, the momentum input to the flow from radiation very rarely exceeds L/c due to two factors: the low opacity of dust to the re-radiated IR and the tendency for dust to be destroyed by sputtering in hot gas environments. Develop simplification of radiative transfer algorithm with the essential physics but much easier to implement, and is faster.
1203.6063
Is IRAS 01072+4954 a true Seyfert 2? Hints from near infrared integral field spectroscopy
Valencia, Zuther, Eckart, Garcia-Marin, Iserlohe, Wright
Some X-ray obscured Seyfert 2 galaxies discovered, in contrast to the unified model. This galaxy has type-1 x-ray emission, while its optical spectrum resembles an HII galaxy and lacks the expected broad lines. IR observations show litter obscuration toward the nucleus; unresolved hot-dust emission (T~1150K) seems to indicate presence of a torus with axis close to the LoS. This galaxy Hosts low mass BH with an estimated mass of 1e5 Msun and bolometric luminosity 2.5e42 erg/s, which yields a high accretion rate (Eddington ratio ~0.2). This system should show broad absorption lines if the relation from more massive system applies; evidence not conclusive. Source seems not to be a true Seyfert-2, but an extreme case of a narrow line Seyfert 1, which due to the faintness of the active nucleus, does not have strong FeII emission in the optical.
1203.6066
Towards an optimal reconstruction of baryon oscillations
Tassev, Zaldarriaga
BAO acoustic peak is smeared and shifted by bulk flows and NL evolution; possible to sharpen the peak and remove the shift by undoing the effects of the bulk flows. Propose improvement to this method: no free parameters, treats large scale modes insistently, and uses optimal filters to extract BAO info. At z=1, the reconstructed linear matter power spectrum leads to a markedly improved sharpening of the reconstructed acoustic peak compared to standard reconstruction.
* Is this operated on simulations? How exactly does the method differ from previous methods? Not enough information!
1203.6069
The mean star formation rate of x-ray selected active galaxies and its evolution from z=2.5: results from PEP-Herschel
Rosario, Santini, et al
Studies of intrinsic IR AGN SEDs: show majority of the FIR emission in AGNs is produced by cold dust heated by SF. Redshift dependent trends in L_fir and L_agn: at low L_agn, accretion and SFR are uncorrelated at all z (most low luminosity AGNs are primarily fueled by secular processes). At high AGN luminosities, significant correlation between L_fir and L_agn, but only at low and moderate redshifts (z<1; interpret as increasing importance of major mergers in both BH growth and increase in SFR). Enhancement of SFR in luminous AGN weakens at z>1; suggests mergers less important at these epochs. At all z, find no relationship between L_fir and nuclear obscuration across five orders of magnitude in column density; suggest various different mechanisms likely to be responsible for obscuring X-rays in active galaxies. Explain results within a scenario in which two different modes of SMBH fueling operate among low-and high-luminosity AGNs. Postulate that the dominant mode of accretion among high-luminosity AGNs evolves with redshift.
* too much information presented in a not-so-clear manner. need to read carefully.
1203.6071
A quasar catalog with simultaneous UV, optical and X-ray observations by Swift
Wu, Berk, Grupe, Koch, Gelbord, Schneider, Gronwall, Wesolowski, Porterfield
Optically selected quasars: simultaneous UV/optical and X-ray observations by Swift GRB explorer: match SDSS DR5 quasar catalog with Swift pointings. 843 objets (637 have both UVOT and XRT observations, 354 detected by both instruments). X-ray detection rate is 60%, which rises to 85% among sources with at least 10ks of XRT exposure time. Construct time-averaged SED for 354 quasars using UVOT photometric measurements and XRT spectra. Find big blue bump contributes about 0.3 dex to the quasar luminosity. Revisit alpha_ox-L_uv relation by selecting a clean sample with only type 1 radio-quiet quasars (dispersion reduced by 15%) Find a weak corruption between L/L_Edd and alpha_uv. Do not find significant correlations between alpha_x and alpha_ox...
1203.6075
The formation of the first massive black holes
Haiman
SMBH common in local galactic nuclei, and M~1e6 Msun SMBH already present at z~6. The earliest SMBHs may grow by the combination of radiation-pressure-limited accretion and mergers of stellar-mass seed BHs, left behind by the first generation of metal-free stars, or may be formed by more rapid direct collapse of gas in rare special environments where dense gas can accumulate without first fragmenting into stars. Review two competing scenarios, along with other exotic alternatives. How can these models be distinguished by JWST, eLISA and other instruments? [a review article]
1203.6076
Observational constraints on gauge field production in axion inflation
Meerburg, Pajer
* axion: a particle field which resolves the strong CP problem (i.e., why QCD does not violate the CP symmetry). If this particle exists and has a low mass, then they are good CDM candidates.
Models of axion inflation: provide natural justification for the flatness of the potential over a super-Planckian distance (the approximate shift-symmetry of the inflation); most observational consequences directly related to this symmetry. During inflation the shift-symmetric couple to a gauge field may happen in large tensor modes, give a very distinct modification of the primordial curvature perturbations. Compare these predictions with observations. Find: leading constraint on the model comes from the CMB power spectrum (WMAP7, ACT). Bispectrum generated by non-Gaussian inverse-decay of the gauge field gives slightly weaker constraints. Constraints from mu-distortion as well, but much weaker. Generalization of the model to massive gauge fields; when mass is generated by some light Higgs fields, observably large local non-Gaussianity can be produced.
1203.6081
THe recent stellar archeology of M31 -- the nearest red disk galaxy
Davidge, et al
SFH of M31 disk during the past few hundred Myr. LF shows that at R>21 kpc (>4 disk scale lengths), constant SFR; but at smaller R, LF suggest that SFR was 2-3x higher in the past 10Myr than the preceding 100 Myr. Rings of cool gas harbor a significant fraction of the current star-forming activity traced by stars with ages ~100 Myr, indicating that (1) these structures have age of >100 Myr and (2) stars in these structures do not follow the same relation between age and random velocity as their counterparts. ... This structure may be the consequence of interactions with a companion galaxy.
1203.6163
Gas density profile in DM halo in chameleon cosmology
Terukina, Yamamoto
* Chameleon particle: postulated scalar particle wit ha NL self-interacitn which gives the particle an effective mass that depends on its environment: the presence of other fields.
Find: gas distribution becomes compact because larger pressure gradient is necessary due to the additional chameleon force.
1203.6205
Improving three-dimensional mass mapping with weak gravitational lensing through a synergy with galaxy clustering
Simon
1203.6248
A decrease of the gas exchanges between galaxies and the IGM, from 12 to 6 billion years ago
Rodrigues, Puech, Hammer, Rothberg, Flores
6 Byr ago, galaxies had mean gas fraction of 32%, twice that of z=0 counterparts. Measured from 65 intermediate mass galaxies at z~0.6. Main ingredients of chemical evolution: SFR, gas mass, stellar mass, metal abundance. Gas fraction increases at 4%/yr from z=0 to 2.2; < 4% of z~0.6 galaxies are undergoing outflow events, in sharp contrast with z~2.2 galaxies. Coevolution of metals and gas over the past 6 Gyr favors a scenario in which the population of intermediate mass galaxies evolved as closed-systems, converting their own gas reservoirs into stars.
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